What if we just increase the number of spaces? Perhaps...
...

It's not GUARANTEED to work.

Well, technically, true in the general case; but I would think if the user
had a handle on the type of text he/she would be processing, then it could
be fine to use it. For example, the OP appeared to be obtaining a filename
from the end of the URL. Filenames should not be longer than 256, but I've
never seen one anywhere near that long in my entire computer career (which
goes back to the early 1980s). I'm guessing there are some practical limits
on what to expect in the length of a URL as well (I'm guessing the 260
character limit wouldn't apply, but I don't think I have ever seen one even
approaching 500 characters). It would seem that in all but a most extreme,
anomalous situation that using 255 spaces in the formula I posted should
work fine. I would be surprised if the OP could not use the formula I posted
with complete confidence.

--
Rick (MVP - Excel)